题解 | 统计快递运输时长

with type_hour as(
    select et.exp_number,
           et.exp_type,
           TIMESTAMPDIFF(minute, ea.out_time, ea.in_time) / 60.0 as hour
    from express_tb et inner join exp_action_tb ea 
    on et.exp_number = ea.exp_number)

select exp_type,
       round(AVG(hour), 1) as time
    from type_hour
    group by exp_type
    order by AVG(hour)